That’s a hard question to answer as every clinical trial treatment is very different.

Some clinical trials stop at phase one, as there is not enough information to prove it is a good treatment for stopping cancer, while other clinical trial treatments can get approval to be used in the NHS. If you are asked to take part in a clinical trial, ask your doctor what the evidence is for doing the trial, what is the success rate of the treatment. They will be able to provide you with this information, it might be some you want to consider before deciding to take part.